JPH0328909Y2 - - Google Patents

Description

[Detailed description of the device] A. Purpose of the device (industrial application field) This device is a device that can be used in a synthetic resin stirring tank used to stir and mix another liquid or solid in a liquid. It is.

(Prior Art) Synthetic resin tanks manufactured by rotational molding are used in various sizes for storing water and chemical solutions, and for various other purposes.

In this application, sewage is put into a tank, chemicals are added, mixed with an agitator, and sterilized.
When treating sewage discharged from a tank or dissolving a disinfectant for fruit trees in water, other liquids, powders, or granular solids may be added to the liquid and mixed by stirring in the tank.

Taking the case of sewage treatment as an example, as shown in Figure 4, sewage is poured into tank 1, chemicals such as sodium hypochlorite, ferric chloride, and caustic soda are added to it, and a propeller-type, stirring system is used. Rotating stirrer such as rod type 2
Stir the wastewater and mix it with the chemicals you put in.

When mixing a liquid with another liquid or solid in this way, if the rotating shaft 3 of the stirrer is located at the center of the cylindrical tank 1 as shown in Figure 4, the liquid will flow along the inner surface of the tank. A circular motion as shown by arrow a in FIG. 5 occurs, and good mixing is not achieved.

As shown in Fig. 6, if the rotating shaft 3 of the stirrer is placed at an eccentric position away from the center of the tank, the rotational vertical movement of the liquid will be asymmetrical with respect to the rotating shaft 3 as shown by arrows b and c, and chemicals, etc. Good mixing is achieved.

However, it is sometimes not possible to install the stirrer eccentrically due to equipment constraints, and the stirrer is often installed in the center of the tank.

In this case, in order to increase the stirring effect and improve the mixing of chemicals, etc., vertical protrusions 4 are formed on the inner surface of the tank as shown in Fig. 7, and the liquid flows in a circle as shown by arrow a in Fig. 5. Efforts have been made to disrupt the motion to create an up-and-down motion component to improve mixing. To form the protrusion 4, one side 5 of the elongated plate is welded to the inner surface of the tank.

(Problem that the invention attempts to solve) In rotary molding used for manufacturing large tanks,
Polyethylene is used as the tank material, but although this resin has strong chemical resistance, it loses strength when welded.
Moreover, since the molecular structure changes due to welding, cracks are more likely to occur due to surfactants and neutral detergents.

Furthermore, when the elongated plate is welded to the inner surface of the tank to form the protrusion 4, a retention area 6 is formed near the welded part between the inner surface of the tank and the elongated plate, where the flow velocity of the liquid is significantly reduced.
(Dead Space) is formed, and the liquid and chemicals stagnate in this area, making it difficult to mix them.

The present invention aims to provide a stirring tank made of synthetic resin and having protrusions that can disturb the flow of liquid without having such drawbacks.

B. Structure of the invention (Means for solving the problems) The present invention has the side wall of a cylindrical synthetic resin tank protruding inward with a V-shaped cross section to form longitudinal protrusions 4.
The above problem was solved by obtaining a synthetic resin stirring tank in which the front surface of the protrusion 4 facing the liquid flow during stirring is approximately perpendicular to the inner surface of the tank in front of the protrusion 4. It is.

(Function) The synthetic resin stirring tank of the present invention has a V-shaped cross section, a thick base, and a vertical protrusion whose front surface is approximately perpendicular to the inner surface of the tank is integrally formed at the same time as the tank body is formed during rotational molding. Therefore, good mixing can be achieved even when a rotary stirrer is installed in the center of the tank, without degrading the strength and chemical resistance or creating a stagnation area during stirring, as would be the case with long thin plate welding. .

(Example) Figures 1 to 3 schematically show an example of the present invention, where Figure 1 is a side view, Figure 2 is a cross-sectional view taken along line A-A in Figure 1, and Figure 3 is a cross-sectional view taken along line A-A in Figure 1.
The figure is an enlarged view of part B in FIG. 2.

A side wall of a polyethylene tank 1 is recessed inward to have a V-shaped cross section to form a vertical protrusion 4. As shown in FIG. 3, the protrusion 4 has a front surface 4a facing the flow of liquid in the direction of the arrow a which moves circularly along the inner surface of the tank due to the agitator, and is approximately perpendicular to the inner surface of the tank.
The liquid flow that collides with this is disturbed to cause the inside of the tank to rise over the protrusion 4 as shown in FIG. Even if both sides of the protrusion 4 are formed flat, since the protrusion 4 has a V-shaped cross section and is thick at the base that contacts the inner surface of the tank, there is little concern that it will form a stagnation part like a conventional elongated plate, but in this embodiment, The rear surface 4b is rounded and recessed so that the liquid flowing over the protrusion 4 smoothly flows into the tank inner surface along the rear surface 4b so that it continues smoothly to the tank inner surface, thereby forming a stagnation part. Preventing.

The outer surface of the tank is covered entirely or partially in the vertical direction with a steel reinforcing frame 7 and is tightly attached to protect it. will not flex and distort its shape or create local stresses in the tank.

C. Effect of the invention 1 Even when a rotary stirrer is installed in the center of the tank, the circular motion of the liquid in the direction of arrow a (FIG. 5) is disturbed to ensure good mixing of the liquid and chemicals.

2. Since the protrusions 4 can be formed at the same time as the tank 1 is rotationally molded, the conventional process of welding an elongated plate to the inner surface of the tank is no longer necessary.
The time required for production is also short.

3. Since no welding is performed, the strength and chemical resistance of the tongue wall will not be degraded by the protrusions.

4. The protrusion 4 has a thick base and the front surface is approximately perpendicular to the inner surface of the tank, so that the liquid can be stirred well and no liquid stagnation occurs at the rear.

[Brief explanation of the drawing]

Figures 1 to 3 schematically show examples of the present invention, Figure 1 is a side view of a synthetic resin tank, and Figure 2 is A of Figure 1.
-A sectional view, Figure 3 is an enlarged view of part B in Figure 2, Figures 4 to 7 schematically show conventional examples, and Figure 4 shows a rotary agitator installed in the center of a tank without ridges. Figure 5 is a cross-sectional view taken along the line C-C in Figure 4, and Figure 6 is a longitudinal cross-section of the tank showing the flow of liquid when the rotary agitator is installed at an eccentric position. side view,
FIG. 7 is a sectional view similar to FIG. 5 of a tank having protrusions on its inner surface. 1: Tank, 2: Rotating stirrer, 3: Rotating shaft,
4: Projection, 4a: Front surface, 4b: Rear surface, 5: One side of the elongated plate, 6: Retention part, 7: Reinforcement frame.

Claims (1)

[Scope of utility model registration request] The side wall of the cylindrical synthetic resin tank is made to protrude inward with a V-shaped cross section to form a vertical protrusion 4, and the front surface of the protrusion 4 facing the liquid flow during stirring is A synthetic resin stirring tank that is approximately perpendicular to the inner surface of the front tank.